One of the primary issues in the heated controversy over the oil and natural gas extraction process called hydraulic fracturing (or fracking) has been the concealment of the chemicals and other substances injected underground, which can potentially contaminate the environment through numerous pathways. Limited voluntary or state-mandated disclosure has revealed a few of the substances.

In an effort to increase transparency, a new Web site called FracFocus provides some limited information on substances used in specific wells. The disclosure is voluntary, only certain companies are participating, there is no information for some wells, and where information is provided, it is only for fracking operations begun after Jan. 1, 2011. But the site (developed by the Ground Water Protection Council and the Interstate Oil and Gas Compact Commission, each of which represents certain government agencies) can provide one starting point for your coverage of this angle.

Another tool for covering fracking substances is a report released April 16, 2011, by Democratic leaders of three House panels: the full Energy and Commerce and Natural Resources Committees and the Energy Subcommittee on Oversight and Investigations. The report identifies 750 substances that were used from 2005-2009 and were voluntarily reported by 14 leading companies after they were asked to do so in 2010. About 780 million gallons of these products were injected underground, in addition to the water used to create the fracking slurries.

The list includes 29 known or possible human carcinogens, substances regulated under the Safe Drinking Water Act, or hazardous air pollutants covered by the Clean Air Act. These toxic substances were used in about 26% of the fracking products.

Ranking Democratic panel leaders Henry Waxman (CA), Edward Markey (MA), and Diana DeGette (CO) say this is the most comprehensive tally yet developed. They note it remains incomplete, in part because even the fracking companies themselves don't know the identity of some of the proprietary chemicals they are injecting underground; about 11% of the fracking products used contained at least one of the proprietary substances.

Additional disclosure of fracking substances may be occurring through new programs initiated by the Wyoming Oil and Gas Conservation Commission in 2010 and the Arkansas Oil and Gas Commission in 2011. However, the state of Wyoming is allowing some of the substances to remain concealed, and in Arkansas the disclosure process is still in the beginning stages, with only a few companies currently disclosing any of their substances.

Wyoming Oil and Gas Conservation Commission: To see the disclosed fracking data, you have to navigate to it via the WOGCC website menu system. Begin here.[6] On the far right, below the top of the page, there is a menu item labeled "Notices Memo's & Detail." Click on this, and you will come to a page headed "Important Notices, Memos, & etc." There is a menu of 10 choices on this page -- click on the fifth item, labeled "Approved Trade Secrets." This will take you to a menu of nine companies. Each time you click on a company, you will arrive at a set of letters for that particular company. When you reach the correct menu, your navigation bar will say http://wogcc.state.wy.us/ap_trade_secrets_new.cfm[7], even though you can't go there directly by typing that address in.